Condenser, and centrifugal chiller equipped with the same

ABSTRACT

The present invention makes it possible in a centrifugal chiller utilizing a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG to effectively extract, in high concentration, non-condensible gas that has mixed into the low pressure refrigerant, and thus suppresses reductions in condensing efficiency. This condenser (3) is equipped with: a shell vessel (21) into which a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG is introduced; a refrigerant inlet (22) which is provided to the top portion of the shell vessel (21); a refrigerant outlet (23) which is provided to the bottom portion of the shell vessel (21); a heat transfer tube bundle (25) in which a plurality of heat transfer tubes (25a) circulating a chilled liquid in the interior thereof are bundled, and which extends along the interior of the shell vessel (21); a gas extraction tube (31) in the heat transfer tube bundle interior, the gas extraction tube being disposed in the center region in the radial direction of the heat transfer tube bundle (25), forming a tubular shape arranged parallel to the axial direction of the heat transfer tube bundle (25), and having formed in the bottom surface thereof non-condensible gas extraction holes (31a) for extracting non-condensible gas that has mixed into the low pressure refrigerant; and a gas extraction device (33) which is connected to the gas extraction tube (31) in the heat transfer tube bundle interior and extracts the non-condensible gas.

TECHNICAL FIELD

The present invention relates to a condenser gasifying a low pressurerefrigerant, and a centrifugal chiller provided with the same.

BACKGROUND ART

For example, as a centrifugal chiller used as a heat source for districtcooling and heating, a centrifugal chiller configured to include a turbocompressor that compresses a refrigerant, a condenser that condenses thecompressed refrigerant, an expansion valve that expands the condensedrefrigerant, and an evaporator that evaporates the expanded refrigerantis known.

Generally, a condenser includes a shell container having a cylindricalshell shape extending in a horizontal direction, and a heat transferpipe bundle is installed so as to penetrate the shell container in alongitudinal direction. The heat transfer pipe bundle is constituted ofa number of heat transfer pipes which are bundled at narrow intervalsand cause a cooling liquid such as water to circulate therein. The heattransfer pipe bundle is laid out so as to pass through the inside of theshell container in the horizontal direction, in other words, thelongitudinal direction.

A high temperature high pressure refrigerant gas compressed by a turbocompressor flows into the shell container through a refrigerant inletprovided in an upper portion thereof, comes into contact with the heattransfer pipe bundle having a large surface area, and is subjected toheat exchange, thereby being cooled and condensed. The refrigerant gasbecomes a refrigerant liquid and is fed to an evaporator side through arefrigerant outlet provided in a lower portion of the shell container.

Low pressure refrigerants such as R1233zd used at a maximum pressure ofless than 0.2 MPaG are expected as next generation refrigerants becausethey can improve efficiency of a centrifugal chiller and have a lowglobal warming potential. However, due to the characteristics of the lowpressure refrigerants, when a suction force of the turbo compressoracts, there are cases where a part of the inside of a refrigerantpassage may be under a negative pressure. In this case, anon-condensable gas (air or the like) may sometimes be incorporated intothe refrigerant passage from the outside through a gap or the like of ashaft sealing. In this manner, the non-condensable gas which has beenincorporated into the refrigerant passage stays in the condenser, causesdeterioration in condensation efficiency, and impairs performance as acold instrument.

PTL 1 discloses a condenser in which a non-condensable gas stayinginside the condenser is separated from a refrigerant gas and is removedby an air bleeding device. As a separation method thereof, thenon-condensable gas is subjected to air bleeding together with therefrigerant gas by the air bleeding device, and they are cooled insidethe air bleeding device. Then, the refrigerant gas is condensed, andonly the non-condensable gas is separated. Since a non-condensable gassuch as air has specific gravity lower than that of a refrigerant andtends to be distributed above inside a condenser, the non-condensablegas distributed above inside a shell container is subjected to airbleeding through an air bleeding port provided in the uppermost portionof the shell container in an air bleeding device in the related art.

CITATION LIST Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2-254271

SUMMARY OF INVENTION Technical Problem

As described above, since a non-condensable gas has specific gravitylower than that of a refrigerant, the non-condensable gas tends to bedistributed in an upper space of a condenser when a centrifugal chillerstops being operated. Therefore, when the centrifugal chiller stopsbeing operated, the non-condensable gas can be efficiently subjected toair bleeding through an air bleeding port provided in an upper portionof a shell container as in the related art.

However, when the centrifugal chiller is operated, a compressedrefrigerant compressed by a turbo compressor is blown down into theshell container through a refrigerant inlet provided in the upperportion of the shell container. Therefore, due to the influence of adescending air flow of the compressed refrigerant, more non-condensablegas is distributed inside a heat transfer pipe bundle, in which thecompressed refrigerant is condensed and liquefied, than in the upperspace of the shell container.

Therefore, the concentration of a non-condensable gas in the upper spaceof the shell container when the centrifugal chiller is operated becomeslower than the concentration inside the heat transfer pipe bundle.Therefore, if air bleeding of a non-condensable gas is performed fromthe upper space of the shell container during an operation, a highpurity refrigerant gas is also subjected to air bleeding together withthe non-condensable gas. Accordingly, there is concern that thenon-condensable gas cannot be efficiently subjected to air bleeding,thereby leading to deterioration in condensation efficiency due to thedepleted refrigerant gas.

The present invention has been made in consideration of suchcircumstances, and an object thereof is to provide a condenser and acentrifugal chiller provided with the same. In the centrifugal chillerusing a low pressure refrigerant used at a maximum pressure of less than0.2 MPaG, it is possible to effectively perform air bleeding in highconcentration with respect to a non-condensable gas which has beenincorporated into the low pressure refrigerant, and it is possible tosuppress deterioration in condensation efficiency.

Solution to Problem

In order to solve the problems, the present invention employs thefollowing means.

According to a first aspect of the present invention, there is provideda condenser including a shell container into which a low pressurerefrigerant used at a maximum pressure of less than 0.2 MPaG isintroduced; a refrigerant inlet which is provided in an upper portion ofthe shell container; a refrigerant outlet which is provided in a lowerportion of the shell container; a heat transfer pipe bundle in which anumber of heat transfer pipes causing a cooling liquid to circulatetherein are bundled and which extends inside the shell container; anintra-heat transfer pipe bundle air bleeding pipe which is disposed in acentral region of the heat transfer pipe bundle in a bundle diameterdirection, which has a pipe shape parallel to an axial direction of theheat transfer pipe bundle, and in which a non-condensable gas airbleeding hole for performing air bleeding of a non-condensable gas mixedin the low pressure refrigerant is formed on a lower surface thereof;and an air bleeding device which is connected to the intra-heat transferpipe bundle air bleeding pipe and performs air bleeding of thenon-condensable gas.

According to the condenser having this configuration, since theintra-heat transfer pipe bundle air bleeding pipe is disposed inside theheat transfer pipe bundle in which a non-condensable gas is maximallydistributed in high concentration when a centrifugal chiller isoperated, it is possible to effectively perform air bleeding in highconcentration with respect to the non-condensable gas which has beenincorporated into a low pressure refrigerant, by operating the airbleeding device. Accordingly, it is possible to suppress deteriorationin condensation efficiency caused by the incorporated non-condensablegas.

A refrigerant gas containing a non-condensable gas is subjected to airbleeding into the intra-heat transfer pipe bundle air bleeding pipethrough the non-condensable gas air bleeding hole, but thenon-condensable gas air bleeding hole is formed on the lower surface ofthe intra-heat transfer pipe bundle air bleeding pipe. Accordingly, acondensed liquid refrigerant is unlikely to flow into thenon-condensable gas air bleeding hole. Therefore, it is possible tosuppress deterioration in condensation efficiency caused by a condensedliquid refrigerant being extracted.

The condenser having the above-described configuration may furtherinclude an extra-heat transfer pipe bundle air bleeding pipe which isdisposed in an upper space inside the shell container, in which anon-condensable gas air bleeding hole is formed on a lower surfacethereof, and which is connected to the air bleeding device. The airbleeding device may be capable of independently performing air bleedingof the non-condensable gas through each of the intra-heat transfer pipebundle air bleeding pipe and the extra-heat transfer pipe bundle airbleeding pipe.

According to the condenser having this configuration, in addition to theintra-heat transfer pipe bundle air bleeding pipe being disposed insidethe heat transfer pipe bundle in which a non-condensable gas ismaximally distributed when the centrifugal chiller is operated, theextra-heat transfer pipe bundle air bleeding pipe is disposed in theupper space inside the shell container in which the non-condensable gasis maximally distributed when the centrifugal chiller is at a stop.Then, the air bleeding device is capable of independently performing airbleeding of the non-condensable gas through each of the intra-heattransfer pipe bundle air bleeding pipe and the extra-heat transfer pipebundle air bleeding pipe.

Therefore, air bleeding is performed through the extra-heat transferpipe bundle air bleeding pipe positioned in the upper space inside theshell container when the centrifugal chiller stops being operated, andair bleeding is performed through the intra-heat transfer pipe bundleair bleeding pipe positioned inside the heat transfer pipe bundle whenthe centrifugal chiller is operated. Accordingly, regardless of anoperational state of the centrifugal chiller, it is possible toeffectively perform air bleeding in high concentration with respect to anon-condensable gas at all times, and it is possible to suppressdeterioration in condensation efficiency caused by the incorporatednon-condensable gas. Naturally, air bleeding may be performed throughboth the intra-heat transfer pipe bundle air bleeding pipe and theextra-heat transfer pipe bundle air bleeding pipe at the same time.

In the condenser having the above-described configuration, the shellcontainer may be configured to have a cylindrical shape extending in ahorizontal direction. The heat transfer pipe bundle may be configured toinclude an outbound pipe bundle which extends from one end to the otherend in a longitudinal direction inside the shell container, and aninbound pipe bundle which communicates with the outbound pipe bundle atthe other end in the longitudinal direction inside the shell containerand returns from the other end to the one end in the longitudinaldirection inside the shell container. The outbound pipe bundle may beconfigured to be disposed below and the inbound pipe bundle may beconfigured to be disposed above inside the shell container. Theintra-heat transfer pipe bundle air bleeding pipe may be configured tobe disposed in a central region of the inbound pipe bundle in the bundlediameter direction.

In this configuration, the intra-heat transfer pipe bundle air bleedingpipe is disposed inside the inbound pipe bundle in which a condensationamount of a gas refrigerant is small because the inbound pipe bundle ispositioned above the outbound pipe bundle and is on a downstream side ofthe outbound pipe bundle. Therefore, there is a low probability that theintra-heat transfer pipe bundle air bleeding pipe will be immersed in aliquid refrigerant, so that it is possible to prevent the liquidrefrigerant from entering the inside of the intra-heat transfer pipebundle air bleeding pipe through the non-condensable gas air bleedinghole and being extracted, and it is possible to suppress deteriorationin condensation efficiency caused by the extracted liquid refrigerant.

According to a second aspect of the present invention, there is provideda centrifugal chiller including a turbo compressor which compresses alow pressure refrigerant used at a maximum pressure of less than 0.2MPaG, the condenser according to any one of claims 1 to 3, whichcondenses the compressed low pressure refrigerant, an expansion valvewhich expands the condensed low pressure refrigerant, and an evaporatorwhich evaporates the expanded low pressure refrigerant. Accordingly, itis possible to exhibit each of the operations and the effects describedabove.

Advantageous Effects of Invention

As described above, according to the condenser of the present inventionand the centrifugal chiller provided with the same, in the centrifugalchiller using a low pressure refrigerant used at the maximum pressure ofless than 0.2 MPaG, it is possible to effectively perform air bleedingin high concentration with respect to a non-condensable gas which hasbeen incorporated into the low pressure refrigerant, and it is possibleto suppress deterioration in condensation efficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a general view of a centrifugal chiller according to anembodiment of the present invention.

FIG. 2 is a perspective view of a condenser illustrated in FIG. 1, andthe diagram illustrates the embodiment of the present invention.

DESCRIPTION OF EMBODIMENT

Hereinafter, embodiments of the present invention will be described withreference to the drawings.

FIG. 1 is a general view of a centrifugal chiller according to anembodiment of the present invention. A centrifugal chiller 1 isconfigured in a unit state including a turbo compressor 2 thatcompresses a refrigerant, a condenser 3, a high-pressure expansion valve4, an economizer 5, a low-pressure expansion valve 6, an evaporator 7, alubricant tank 8, a circuit box 9, an inverter unit 10, an operationpanel 11, and the like. The lubricant tank 8 is a tank storing lubricantsupplied to bearings, a speed increaser, and the like of the turbocompressor 2.

The condenser 3 and the evaporator 7 are formed in cylindrical shellshapes having high pressure resistance and are disposed so as to beparallel and adjacent to each other in a state where their axis linesextend in a substantially horizontal direction. The condenser 3 isdisposed at a position relatively higher than the evaporator 7, and thecircuit box 9 is installed below thereof. The economizer 5 and thelubricant tank 8 are installed while being interposed between thecondenser 3 and the evaporator 7. The inverter unit 10 is installed inan upper portion of the condenser 3, and the operation panel 11 isdisposed above the evaporator 7.

The turbo compressor 2 is a known centrifugal turbine-type compressorwhich is rotatively driven by an electric motor 13. The turbo compressor2 is disposed above the evaporator 7 in a posture having its axis lineextending in the substantially horizontal direction. The electric motor13 is driven by the inverter unit 10. As described below, the turbocompressor 2 compresses a gas-phase refrigerant supplied from theevaporator 7 via a suction pipe 14. A low pressure refrigerant such asR1233zd used at a maximum pressure of less than 0.2 MPaG is used as therefrigerant, for example.

A discharge port of the turbo compressor 2 and a refrigerant inlet 22provided in the upper portion of the condenser 3 are connected to eachother through a discharge pipe 15, and a refrigerant outlet 23 providedin a bottom portion of the condenser 3 and a bottom portion of theeconomizer 5 are connected to each other through a refrigerant pipe 16.In addition, the bottom portion of the economizer 5 and the evaporator 7are connected to each other through a refrigerant pipe 17, and an upperportion of the economizer 5 and a middle stage of the turbo compressor 2are connected to each other through a refrigerant pipe 18. Thehigh-pressure expansion valve 4 is provided in the refrigerant pipe 16,and the low-pressure expansion valve 6 is provided in the refrigerantpipe 17.

In the centrifugal chiller 1 configured as described above, the turbocompressor 2 is rotatively driven by the electric motor 13, compresses agas-phase low pressure refrigerant supplied from the evaporator 7 viathe suction pipe 14, and feeds this compressed low pressure refrigerantto the condenser 3 through the discharge pipe 15.

Inside the condenser 3, when a high temperature low pressure refrigerantcompressed in the turbo compressor 2 is subjected to heat exchange witha cooling liquid such as water, condensed heat is cooled, so that thelow pressure refrigerant is condensed and liquefied. The cooling liquidheated herein is utilized as a heat medium for heating, and the like.The low pressure refrigerant caused to be in a liquid phase by thecondenser 3 expands after passing through the high-pressure expansionvalve 4 provided in the refrigerant pipe 16 extending from the condenser3. The low pressure refrigerant is transported to the economizer 5 in agas-liquid mixed state and is temporarily stored therein.

Inside the economizer 5, the low pressure refrigerant which has expandedthrough the high-pressure expansion valve 4 in a gas-liquid mixed stateis subjected to gas-liquid separation into a gas-phase part and aliquid-phase part. The liquid-phase part of the low pressure refrigerantseparated herein is caused to further expand through the low-pressureexpansion valve 6 provided in the refrigerant pipe 17 extending from thebottom portion of the economizer 5 and becomes a gas-liquid two-phaseflow, thereby being transported to the evaporator 7. In addition, thegas-phase part of the low pressure refrigerant separated in theeconomizer 5 is transported to a middle stage portion of the turbocompressor 2 via the refrigerant pipe 18 extending from the upperportion of the economizer 5 and is compressed again.

Inside the evaporator 7, a low temperature liquid refrigerant which hasadiabatically expanded through the low-pressure expansion valve 6 issubjected to heat exchange with a cooling target liquid such as water,the cooling target liquid which has been cooled herein is used as a coldheat medium for air conditioning or an industrial cooling liquid. Therefrigerant gasified through heat exchange with the cooling targetliquid is suctioned again by the turbo compressor 2 via the suction pipe14 and is compressed. Thereafter, this cycle is repeated.

FIG. 2 is a perspective view of the condenser 3 illustrating theembodiment of the present invention.

The condenser 3 has a cylindrical shape extending in the horizontaldirection as described above and is configured to include a shellcontainer 21 into which a low pressure refrigerant used at the maximumpressure of less than 0.2 MPaG is introduced, the refrigerant inlet 22which is provided in an the upper portion of the shell container 21, therefrigerant outlet 23 which is provided in a lower portion of the shellcontainer 21, a heat transfer pipe bundle 25 which horizontally extendsalong a longitudinal direction inside the shell container 21, and an airbleeding system 30 which serves as a main portion of the presentinvention.

Each of the refrigerant inlet 22 and the refrigerant outlet 23 isdisposed in an intermediate portion of the shell container 21 in thelongitudinal direction. As illustrated in FIG. 1, the refrigerant inlet22 is connected to the discharge port of the turbo compressor 2 via thedischarge pipe 15, and the refrigerant outlet 23 is connected to theeconomizer 5 via the refrigerant pipe 16.

The heat transfer pipe bundle 25 includes an outbound pipe bundle 25Awhich horizontally extends from one end (left end in FIG. 2) to theother end (right end in FIG. 2) in the longitudinal direction inside theshell container 21, and an inbound pipe bundle 25B which communicateswith the outbound pipe bundle 25A at the other end in the longitudinaldirection inside the shell container 21 and horizontally returns fromthe other end to one end in the longitudinal direction inside the shellcontainer 21. Both the outbound pipe bundle 25A and the inbound pipebundle 25B have a known pipe bundle structure in which a number of heattransfer pipes 25 a causing a cooling liquid such as water to circulatetherein are inserted through a plurality of porous heat transfer pipesupport plates (not illustrated) and are bundled.

Inside the shell container 21, the outbound pipe bundle 25A is disposedbelow and the inbound pipe bundle 25B is disposed above. A U-turnchamber (not illustrated) is provided at the other end (right end inFIG. 2) of the shell container 21, and end portions of the outbound pipebundle 25A and the inbound pipe bundle 25B are connected to the U-turnchamber such that they communicate with each other. In addition, at oneend (left end in FIG. 2) of the shell container 21, a nozzle-shapedcooling water inlet (not illustrated) which is connected to one end ofthe outbound pipe bundle 25A, and a nozzle-shaped cooling water outlet(not illustrated) which is positioned above the cooling water inlet andis connected to one end of the inbound pipe bundle 25B are provided.

The cooling liquid flowing in the heat transfer pipe bundle 25 flowsfrom one end of the outbound pipe bundle 25A (left end in FIG. 2)through the cooling water inlet and flows to the other end (right end inFIG. 2). After a U-turn in the U-turn chamber, the cooling liquid flowsfrom the other end (right end in FIG. 2) to one end (left end in FIG. 2)of the inbound pipe bundle 25B and is discharged via the cooling wateroutlet. On the other hand, a high temperature high pressure gasrefrigerant compressed by the turbo compressor 2 enters the inside ofthe shell container 21 through the refrigerant inlet 22 and is dispersedin the longitudinal direction of the shell container 21 by adistribution plate 27. Then, the gas refrigerant comes into contact withthe inbound pipe bundle 25B and the outbound pipe bundle 25A in thisorder, is subjected to heat exchange, and is condensed, thereby becominga liquid refrigerant and being discharged through the refrigerant outlet23.

The air bleeding system 30 serving as the main portion of the presentinvention is a system performing air bleeding of a non-condensable gassuch as air which is likely to be incorporated into a low pressurerefrigerant. The air bleeding system 30 is configured to include anintra-heat transfer pipe bundle air bleeding pipe 31, an extra-heattransfer pipe bundle air bleeding pipe 32, an air bleeding device 33,and partition valves 34 and 35.

The intra-heat transfer pipe bundle air bleeding pipe 31 is disposed ina central region of the inbound pipe bundle 25B in a bundle diameterdirection in the heat transfer pipe bundle 25, has a horizontal pipeshape parallel to an axial direction of the inbound pipe bundle 25B, andhas a plurality of round hole-shaped non-condensable gas air bleedingholes 31 a formed on a lower surface thereof. For example, the length ofthe intra-heat transfer pipe bundle air bleeding pipe 31 is set to be alength corresponding to approximately the entire length of the inboundpipe bundle 25B but may be shorter. A non-condensable gas discharge pipe37 extending upward is connected to one end or the intermediate portionof the intra-heat transfer pipe bundle air bleeding pipe 31. In thepresent embodiment, one end of the intra-heat transfer pipe bundle airbleeding pipe 31 is curved or bent upward and serves as thenon-condensable gas discharge pipe 37 as it stands. The other end of theintra-heat transfer pipe bundle air bleeding pipe 31 is blocked. Thenon-condensable gas discharge pipe 37 penetrates a peripheral surface ofthe shell container 21 upward and is connected to a non-condensable gascollecting pipe 40 extending from the air bleeding device 33, via thepartition valve 34.

For example, the pipe diameter of the intra-heat transfer pipe bundleair bleeding pipe 31 ranges approximately from 15 mm to 20 mm. Forexample, the non-condensable gas air bleeding holes 31 a are bored atintervals of approximately 20 cm along the axial direction, and theirhole diameters range approximately from 5 to 10 mm, for example. If thehole diameters of the non-condensable gas air bleeding holes 31 a areexcessively small, there are cases where the non-condensable gas airbleeding holes 31 a may be liquid-sealed due to surface tension of aliquid refrigerant when being submerged in the liquid refrigerant. Incontrast, if the holes are excessively large, a liquid refrigerant islikely to flow into the intra-heat transfer pipe bundle air bleedingpipe 31 through the non-condensable gas air bleeding holes 31 a. Thehole shapes of the non-condensable gas air bleeding holes 31 a are notnecessarily round hole shapes. For example, it is possible to considerto have square hole shapes, long hole shapes inclined with respect tothe axial direction of the intra-heat transfer pipe bundle air bleedingpipe 31, slit shapes along the axial direction of the intra-heattransfer pipe bundle air bleeding pipe 31, or the like.

In addition, the hole diameters of the non-condensable gas air bleedingholes 31 a may sequentially increase from the outlet side(non-condensable gas discharge pipe 37 side) to the inlet side (tip endside) of the intra-heat transfer pipe bundle air bleeding pipe 31. Inthis manner, it is possible to uniformly perform air bleeding of anon-condensable gas over the entire length of the intra-heat transferpipe bundle air bleeding pipe 31 by reducing the hole diameters on theoutlet side where a suction force is strong (a pressure loss is small)and increasing the hole diameters on the inlet side where a suctionforce is weak (a pressure loss is significant).

On the other hand, the extra-heat transfer pipe bundle air bleeding pipe32 is a pipe-shaped member which is disposed in an upper space insidethe shell container 21, that is, above the outbound pipe bundle 25A andhorizontally extends along the longitudinal direction of the shellcontainer 21. For example, the pipe diameter of the extra-heat transferpipe bundle air bleeding pipe 32 is the same diameter as that of theintra-heat transfer pipe bundle air bleeding pipe 31, andnon-condensable gas air bleeding holes 32 a similar to thenon-condensable gas air bleeding holes 31 a of the intra-heat transferpipe bundle air bleeding pipe 31 are bored on the lower surface thereof.A non-condensable gas discharge pipe 38 extending upward is connected tothe extra-heat transfer pipe bundle air bleeding pipe 32 as well. Thenon-condensable gas discharge pipe 38 penetrates the peripheral surfaceof the shell container 21 upward and is connected to the non-condensablegas collecting pipe 40 extending from the air bleeding device 33, viathe partition valve 35.

The air bleeding device 33 is a known device configured to perform airbleeding of a non-condensable gas such as air which has beenincorporated into a refrigerant in the shell container 21, together witha refrigerant gas. Then, they are cooled, and only the refrigerant gasis condensed and liquefied so as to be separated from thenon-condensable gas. If the air bleeding device 33 is operated, apredetermined negative pressure is applied to the intra-heat transferpipe bundle air bleeding pipe 31 and the extra-heat transfer pipe bundleair bleeding pipe 32 via the non-condensable gas collecting pipe 40 andthe non-condensable gas discharge pipes 37 and 38. Then, thenon-condensable gas, which has been incorporated into the refrigerant inthe shell container 21 together with a part of the refrigerant gasthrough the non-condensable gas air bleeding holes 31 a and 32 a formedin the intra-heat transfer pipe bundle air bleeding pipe 31 and theextra-heat transfer pipe bundle air bleeding pipe 32, is subjected toair bleeding.

As described above, the non-condensable gas discharge pipe 37 extendingfrom the intra-heat transfer pipe bundle air bleeding pipe 31 and thenon-condensable gas discharge pipe 38 extending from the extra-heattransfer pipe bundle air bleeding pipe 32 are connected to thenon-condensable gas collecting pipe 40 extending from the air bleedingdevice 33 via the partition valves 34 and 35 respectively. The airbleeding device 33 is capable of independently performing air bleedingof a non-condensable gas through each of the intra-heat transfer pipebundle air bleeding pipe 31 and the extra-heat transfer pipe bundle airbleeding pipe 32 by opening the partition valve or the partition valve35. In addition, it is also possible to perform air bleeding of anon-condensable gas from both the intra-heat transfer pipe bundle airbleeding pipe 31 and the extra-heat transfer pipe bundle air bleedingpipe 32 by opening both the partition valves 34 and 35. Moreover, theratio of air bleeding in the intra-heat transfer pipe bundle airbleeding pipe 31 and the extra-heat transfer pipe bundle air bleedingpipe 32 can be varied by varying valve-opening degrees of the partitionvalves 34 and 35.

The condenser 3 is configured as follows.

In the condenser 3, the intra-heat transfer pipe bundle air bleedingpipe 31, which is connected to the air bleeding device 33 and throughwhich a non-condensable gas such as air that has been incorporated intoa refrigerant inside the shell container 21 is subjected to airbleeding, is disposed in the central region of the heat transfer pipebundle 25 (inbound pipe bundle 25B) in the bundle diameter direction andis provided to be parallel to the axial direction of the heat transferpipe bundle 25. According to this configuration, since the intra-heattransfer pipe bundle air bleeding pipe 31 is disposed inside the heattransfer pipe bundle 25 in which a non-condensable gas is maximallydistributed in high concentration when the centrifugal chiller 1 isoperated, it is possible to effectively perform air bleeding in highconcentration with respect to the non-condensable gas which has beenincorporated into a low pressure refrigerant, by operating the airbleeding device 33. Accordingly, it is possible to suppressdeterioration in condensation efficiency caused by the incorporatednon-condensable gas.

A refrigerant gas containing a non-condensable gas is subjected to airbleeding into the intra-heat transfer pipe bundle air bleeding pipe 31through the plurality of non-condensable gas air bleeding holes 31 a,but the non-condensable gas air bleeding holes 31 a are formed on thelower surface of the intra-heat transfer pipe bundle air bleeding pipe31, a condensed liquid refrigerant is unlikely to flow into thenon-condensable gas air bleeding holes 31 a. Therefore, it is possibleto suppress deterioration in condensation efficiency caused by acondensed liquid refrigerant being extracted.

In addition, in the outbound pipe bundle 25A and the inbound pipe bundle25B configuring the heat transfer pipe bundle 25, the intra-heattransfer pipe bundle air bleeding pipe 31 is disposed in the centralregion of the inbound pipe bundle 25B in the bundle diameter directionin which a condensation amount of a gas refrigerant is small because theinbound pipe bundle 25B is positioned above the outbound pipe bundle 25Aand is on a downstream side of the outbound pipe bundle 25A. Therefore,there is a low probability that the intra-heat transfer pipe bundle airbleeding pipe 31 will be immersed in a liquid refrigerant, so that it ispossible to prevent the liquid refrigerant from entering the inside ofthe intra-heat transfer pipe bundle air bleeding pipe 31 through thenon-condensable gas air bleeding holes 31 a and being extracted, and itis possible to suppress deterioration in condensation efficiency causedby the extracted liquid refrigerant.

In addition, the condenser 3 further includes the extra-heat transferpipe bundle air bleeding pipe 32 which is disposed outside the heattransfer pipe bundle 25 (25B) and in the upper space inside the shellcontainer 21. The extra-heat transfer pipe bundle air bleeding pipe 32is connected to the air bleeding device 33, and the non-condensable gasair bleeding holes 32 a are formed on the lower surface thereof. Then,the air bleeding device 33 is capable of independently performing airbleeding of a non-condensable gas through each of the intra-heattransfer pipe bundle air bleeding pipe 31 and the extra-heat transferpipe bundle air bleeding pipe 32.

According to this configuration, in addition to that the intra-heattransfer pipe bundle air bleeding pipe 31 is disposed inside the heattransfer pipe bundle 25 (25B) in which a non-condensable gas ismaximally distributed when the centrifugal chiller 1 is operated, theextra-heat transfer pipe bundle air bleeding pipe 32 is disposed in theupper space inside the shell container 21 in which the non-condensablegas is maximally distributed when the centrifugal chiller 1 is at astop. Then, the air bleeding device 33 is capable of independentlyperforming air bleeding of the non-condensable gas through each of theintra-heat transfer pipe bundle air bleeding pipe 31 and the extra-heattransfer pipe bundle air bleeding pipe 32.

Therefore, air bleeding can be performed through the extra-heat transferpipe bundle air bleeding pipe 32 positioned in the upper space insidethe shell container 21 when the centrifugal chiller 1 stops beingoperated, and air bleeding can be performed through the intra-heattransfer pipe bundle air bleeding pipe 31 positioned inside the heattransfer pipe bundle 25 (25B) when the centrifugal chiller 1 isoperated. Accordingly, regardless of an operational state of thecentrifugal chiller 1, it is possible to effectively perform airbleeding in high concentration with respect to a non-condensable gas atall times, and it is possible to suppress deterioration in condensationefficiency caused by the incorporated non-condensable gas. Naturally,air bleeding may be performed through both the intra-heat transfer pipebundle air bleeding pipe 31 and the extra-heat transfer pipe bundle airbleeding pipe 32 at the same time.

As described above, according to the condenser 3 of the presentembodiment and the centrifugal chiller 1 provided with the condenser 3,in the centrifugal chiller using a low pressure refrigerant used at themaximum pressure of less than 0.2 MPaG, it is possible to effectivelyperform air bleeding in high concentration with respect to anon-condensable gas which has been incorporated into the low pressurerefrigerant, and it is possible to suppress deterioration incondensation efficiency.

The present invention is not limited to only the configurations of theembodiment described above, and changes or modifications can be suitablyadded. An embodiment having such changes or modifications added theretois also included in the scope of rights of the present invention.

For example, in the embodiment, one intra-heat transfer pipe bundle airbleeding pipe 31 and one extra-heat transfer pipe bundle air bleedingpipe 32 are provided, but there may be provided two or more each. Inaddition, in the embodiment, the intra-heat transfer pipe bundle airbleeding pipe 31 is installed inside the inbound pipe bundle 25Bconfiguring an upper portion of the heat transfer pipe bundle 25, but itmay be installed inside the outbound pipe bundle 25A configuring a lowerportion of the heat transfer pipe bundle 25.

REFERENCE SIGNS LIST

-   1 CENTRIFUGAL CHILLER-   2 TURBO COMPRESSOR-   3 CONDENSER-   4, 6 EXPANSION VALVE-   7 EVAPORATOR-   21 SHELL CONTAINER-   22 REFRIGERANT INLET-   23 REFRIGERANT OUTLET-   25 HEAT TRANSFER PIPE BUNDLE-   25A OUTBOUND PIPE BUNDLE-   25B INBOUND PIPE BUNDLE-   25 a HEAT TRANSFER PIPE-   31 INTRA-HEAT TRANSFER PIPE BUNDLE AIR BLEEDING PIPE-   31 a, 32 a NON-condensable GAS AIR BLEEDING HOLE-   32 EXTRA-HEAT TRANSFER PIPE BUNDLE AIR BLEEDING PIPE-   33 AIR BLEEDING DEVICE

1. A condenser comprising: a shell container into which a low pressurerefrigerant used at a maximum pressure of less than 0.2 MPaG isintroduced; a refrigerant inlet which is provided in an upper portion ofthe shell container; a refrigerant outlet which is provided in a lowerportion of the shell container; a heat transfer pipe bundle in which anumber of heat transfer pipes causing a cooling liquid to circulatetherein are bundled and which extends inside the shell container; anintra-heat transfer pipe bundle air bleeding pipe which is disposed in acentral region of the heat transfer pipe bundle in a bundle diameterdirection, which has a pipe shape parallel to an axial direction of theheat transfer pipe bundle, and in which a non-condensable gas airbleeding hole for performing air bleeding of a non-condensable gas mixedin the low pressure refrigerant is formed on a lower surface thereof;and an air bleeding device which is connected to the intra-heat transferpipe bundle air bleeding pipe and performs air bleeding of thenon-condensable gas.
 2. The condenser according to claim 1, furthercomprising: an extra-heat transfer pipe bundle air bleeding pipe whichis disposed in an upper space inside the shell container, in which anon-condensable gas air bleeding hole is formed on a lower surfacethereof, and which is connected to the air bleeding device, wherein theair bleeding device is capable of independently performing air bleedingof the non-condensable gas through each of the intra-heat transfer pipebundle air bleeding pipe and the extra-heat transfer pipe bundle airbleeding pipe.
 3. The condenser according to claim 1, wherein the shellcontainer has a cylindrical shape extending in a horizontal direction,wherein the heat transfer pipe bundle includes an outbound pipe bundlewhich extends from one end to the other end in a longitudinal directioninside the shell container, and an inbound pipe bundle whichcommunicates with the outbound pipe bundle at the other end in thelongitudinal direction inside the shell container and returns from theother end to the one end in the longitudinal direction inside the shellcontainer, wherein the outbound pipe bundle is disposed below and theinbound pipe bundle is disposed above inside the shell container, andwherein the intra-heat transfer pipe bundle air bleeding pipe isdisposed in a central region of the inbound pipe bundle in the bundlediameter direction.
 4. A centrifugal chiller comprising: a turbocompressor which compresses a low pressure refrigerant used at a maximumpressure of less than 0.2 MPaG; the condenser according to claim 1,which condenses the compressed low pressure refrigerant; an expansionvalve which expands the condensed low pressure refrigerant; and anevaporator which evaporates the expanded low pressure refrigerant. 5.The condenser according to claim 2, wherein the shell container has acylindrical shape extending in a horizontal direction, wherein the heattransfer pipe bundle includes an outbound pipe bundle which extends fromone end to the other end in a longitudinal direction inside the shellcontainer, and an inbound pipe bundle which communicates with theoutbound pipe bundle at the other end in the longitudinal directioninside the shell container and returns from the other end to the one endin the longitudinal direction inside the shell container, wherein theoutbound pipe bundle is disposed below and the inbound pipe bundle isdisposed above inside the shell container, and wherein the intra-heattransfer pipe bundle air bleeding pipe is disposed in a central regionof the inbound pipe bundle in the bundle diameter direction.
 6. Acentrifugal chiller comprising: a turbo compressor which compresses alow pressure refrigerant used at a maximum pressure of less than 0.2MPaG; the condenser according to claim 2, which condenses the compressedlow pressure refrigerant; an expansion valve which expands the condensedlow pressure refrigerant; and an evaporator which evaporates theexpanded low pressure refrigerant.
 7. A centrifugal chiller comprising:a turbo compressor which compresses a low pressure refrigerant used at amaximum pressure of less than 0.2 MPaG; the condenser according to claim3, which condenses the compressed low pressure refrigerant; an expansionvalve which expands the condensed low pressure refrigerant; and anevaporator which evaporates the expanded low pressure refrigerant.